Conventionally, there has been known a wireless mouse that performs short-range wireless communication with a computer (e.g. see Japanese Laid-Open Patent Application Publication No. 2011-81805). There has been known a dongle to be used when a guest device is connected to a wireless home network (e.g. see Japanese National Publication of International Patent Application No. 2007-528057).
In addition, there has been known a system in which a main device communicates wirelessly with a client device. In this system, an identification number of the client device is ordinarily preset to the main device, and an identification number of main device is ordinarily preset to the client device. Thereby, the main device communicates wirelessly with only the client device of the preset identification number, and the client device communicates wirelessly with only the main device of the preset identification number. As a result, the main device and the client device do not interfere with a device of an unset identification number.